THIS invention relates to a steering wheel, and more particularly, to an aluminium steering wheel.
Steering wheels are generally fabricated from a number of different components including a metal rim, spokes, and a central hub which connects to the steering column. The rim is generally covered with a resilient foam material or the like after the metal components have been interconnected. There are various problems with this prior art type of steering wheel including problems relating to connecting the distal ends of the spokes to the rim. Generally the point of connection between the rim and the spokes is found to be a zone of weakness for most wheels.
Steering wheels are safety critical components in most vehicles. It is important that the steering wheel is able to absorb a high impact load and preferably will deform under load rather than break. It is well known that cast materials tend to shatter rather than bend. It is also known that castings often crack and, accordingly, casting processes are not usually considered appropriate for the manufacturer of steering wheels.
Applicant is aware of certain prior art which contemplates cast aluminium steering wheels. European applications nos. EP-A-0292038, EP-A-0412605 and EP-A-0050309 all deal with the concept of cast steering wheels. However, none of the prior art specifications referred to satisfy Applicant's requirements that the steering wheel be cast as a one piece casting, that the wheel is of high strength and relatively resilient, and that it can be made crack-free.